In the technologies related to rail transit control, railway turnout control is one of the basic processes that guarantee the safety and continuity of the operation of rail transit.
A train may pass through a railway turnout area according to a driving plan. From the perspective of space, the driving plan may represent a driving trajectory of the train. The trajectory may be embodied as a specific arrangement and establishment of a route along which the train is to pass through the railway turnout area. The arrangement of the route may correspond to a single record in a list of certain railway turnout with its state. The establishment of the route involves, for the driving safety of the train and at a safety distance ahead of the train, claiming all the railway turnouts included in the single record according to their corresponding state included in the record for the passage of the train.
During an establishment of a route, the claims of all the railway turnouts of the route may be completed at almost the same time. As a train travels along the route, when the train safely passes through a railway turnout of the route (the entire train just leaves the railway turnout and is outside the boundaries of the railway turnout), the claim of the railway turnout may be released (so that the next train to pass through the railway turnout may claim the railway turnout again). Such a situation may occur multiple times until the train safely passes through the route and all the claims of the corresponding railway turnouts are released. The train may continue driving until the next route related to the driving plan is approached and the above process may be repeated. In the end, the train may stop at a stopping point where the end of the trajectory corresponding to the driving plan is located. For operational needs, the stopping point where the end of the trajectory is generally located in an area of a turnback stopping point.
In the commonly acknowledged safety control logic of a railway turnout, conflicting routes are not allowed to be established simultaneously at any moment. A claim of a railway turnout for a train is monopolistic (or exclusive). That is, a certain railway turnout can only be claimed for one train at any moment. A claimed railway turnout can be claimed again only if the claim is released.
It has been found that, the railway turnout control scheme corresponding to the aforementioned driving-plan-guided process for a train passing through a railway turnout area is flawed when being implemented in an area including a turnback stopping point (or be referred to as a “turnback area”). For example, when a train drives into a turnback area and stops, that is, it has not driven out of the turnback area, if another train has established a route into the turnback area, as the turnout has been claimed by the other train, the train stops in the turnback area may not be able to establish a route to drive out of the turnback area. Meanwhile, as the turnback area is occupied, the other train that has established the route into the turnback area may not be able to drive into the turnback area. Eventually, the stalemate of the two trains may cause deadlock situation, which may hinder the normal operation of the turnback area. What's worse, in a scenario having crossed routes, a train conflict may occur.
It can be seen that, in the existing railway turnout control schemes, basic control logics such as “only one of the conflicting routes is allowed to be established for a passage of a train at any moment” and “a railway turnout can only be claimed for one train at any moment” can be easily satisfied, but there are still problems such as deadlock situation of the turnback area and insufficient safety protection for the crossed routes. Such problems may be encountered in the operations of a variety of rail transit systems such as railways, subways, light rail, trams, monorails, maglev trains, etc. As important technical issues of modern signal systems (such as communication based train control system, CBTC) that fully adopt modern techniques related to computers, software, communication, and automatic control, these problems must be addressed.